Earth drill



May 28, 1946.

c. w. KANDLE 2,401,250

EARTH DRILL Filed Sept. 30, 1945 2 Sheets-Sheet 1 Charles WI KindleINVENTOR.

ATTORNEY.

c. w. KANDLE EARTH DRILL May 28, 1946.

Filed Sept. 30, 1943 2 Sheets-Sheet 2 Charles W Kandle ATTOR NEYItherefor; and

Patented May 28, 1946 UNITED STATES PATENT OFFICE I EARTH DRILL Charlesw. Kandie, Chicago, 111. Application September 30, 1943, Serial No.504,343 14 Claims. (Cl. 255-70) This invention relates to earth drillsand more particularly to drill bits and cutting blades adapted to beemployed at the bottom of auger flights and the like for the boring ofholes in the earth similar to the drills set forth in United StatesPatent No. 2,320,612 granted to applicant,

One of the objects of the present invention is to provide a simplebladeconstruction that permits ready replacement of the cutting blade.

Another object is to provide a reversible blade with different cuttingangles for differentpositions of the blade to promote eflicient drillingin different types of soil.

Another object is to prevent clogging of the dirt immediately behind theblade and as it moves onto the flight.

one-quarter of the circumference and providing a space for receiving thecutting blade and for the upward movement of spoil over the blade.

An extra heavy radial rib I borders the forward boundary of sector 6 andcontains hinge brackets 8 for receiving and holding a trapdoor 9covering the open sector 6. The hinge joint or pivot 10 is locatedrelatively high above the plate I and nearly midway between the top ofthe plate and the first flight convolution of the conveyor l3 tofacilitate the upward swinging of door 9 without interference from theauger.

Another object is to provide a more eflicient I trap door for thepassage of dirt over the blade without danger of clogging.

Another object is to protect the outer corner of the blade from wear byproviding an auxiliary cutter ahead of the blade to define the outercircumference of the cut.

An extra heavy radial rib H borders the rear boundar of sector 6 and hasa shoulder l2 along its rear side for receiving the lower end of theconveyor flight Hi. The forward side of the rib II is slanted at about a40 angle from the horizontal in order to give pitch to the cuttingblade.

A blade holder I4 is welded to the top of rib H and extends downwardlyover the slanting face of the rib and in spaced parallel relationthereto for receiving the blade l5 therebetween.

Another object is to provide for quick adjust- The blade i5 has achannel or groove It in each face for registering with a tongue I! inholder l4. As shown the grooves iii are directly opposite one another inthe respective faces of blade l5 so that the blade may be turned overwithout changing the position of its cutting edge.

Fig. 4 is a section through the blade and blade holder taken on line 44of Fig. 2;

Fig. 5 is a section similar to Fig. 4 showing the blade reversed formaking a deeper cut;

Fig. 6 is a similarsection showing the blade turned over toprovide adifferent cutting angle Fig. 7 is a perspective view of the blade whenremoved from its holder. The drill bit comprises in general a cast metalcircular plate Ijhaving a central upstanding cylindrical shank "2 and anouter rim 3. The plate l is relatively thin in the body portion betweenthe central shoulder 4 encircling thev shank 2 and'the thick rim 3, vand has radial spoke-like If desired, a tongue l8 may be provided on theface of rib H and directly opposed to tongue H.

The blade has its edges beveled bluntly to constitute cutting edges 19.-Where both sides are beveled, the bevel on one side should be steeperthan that on the other side of each edge. One cutting edge is preferablydisposed 'ata farther distance from the grooves. i6 than the othercutting edge. This provides for' a reversal of the blade to obtaineither a deep cut in light soils or a shallow cut in heavy soils. If theblade is merely turned over without reversing the same edge for edge,the angle of the cutting edge is changed to suit the soil. It ispossible that more than two cutting depths may be provided for if one ofthe tongues IT or I8 is eliminated and the grooves iii are offsetlaterall from one another so that one is at the center line'of the bladeand the .andvof holder I4 is such as to provide a recess for receivingthe. blade and coveringits unused edge while exposing the cuttingedge'at a depth of fromabout 1% to 1 s inch-below the botto msuriaceofplate l. an open sector 6 preferably constituting less than .55The blad holder It ha its 'front edge lllbev- I it eled and extending toa position short of the shortest bevel on the blade to prevent spoilfrom getting beneath it and prying upwardly.

The position of the blade l5 radially with respect to the holder l4 andplate I is adjustable to provide that the blade extends outwardly beyondthe rim 3, usually from about one-quarter to about one-half inch. Theblade 15 may be held in adjusted radial position by a screw or pin 2|extending downwardly through holder l4 and into the blade. The bladepreferably'has several small holes.22 for receiving the screw 2| in therespective adjusted positions of the blade.

The blade is set a little behind the actual radius from the center ofthe bit so that it has a tendency' to crowd the spoil inwardly towardthe center as the spoil passes upwardly over the blade. The trap door 9has the axis of its hinges nearly parallel to the rib It so that thedoor will rise freely until it engages the next convolution of thespiral flight 13 without interference'from the central shank 2.

In order to prevent undesirable wear of the,

outer corner of blade IS, an auxiliary cutter in the form of a bluntnosed pin 23 is disposed in the outer comer of rib 1 and set at an angleto extend diagonally downwardly from plate I and outwardly from rim 3 adistance equal to or greater than the corresponding position for theouter corner of blade 15. The cutter 23 may be held in place by a setscrew 24 extending from the back of rib I. The relatively inexpensivecutter 23 serves to break up the soil at the outer edge of the boreahead of the blade l5 and thereby prevent undue wear of the blade.

The bit is ordinarily secured to the lower end of an auger or conveyorflight i3 by entry of shank 2 into the central vertical tube 25 of theflight. Rotation of the bit with the flight is obtained by bolt 26passing through the tube 25 .and shank 2. A suitable central lead screw21 may be provided for additionally centering the bit in the hole andkeeping it from jumping up and down during drilling.

'I'heflight I 3 comprises a sheet metal spiral encircling the centraltube 25 and edge welded thereto. The lower end of flight 13 has its edgeout to fit upon shoulder l2 just behind the top of the weld 28 of. bladeholder It. The inner portion 29 of the lower edge of the flight is cutand bent downwardly to fill the gap between rib H and tube 25.

In drilling the spoil rises over blade i5 and holder l4 and fallsimmediately upon flight l3 where it is gradually pushed upwardly as morespoil begin to rise. By bringing the lower edge of the flight directlyto the top of the rib i I and holder i4, it has been found that there isno clogging of spoil at this point. Where the flight is dropped to restupon plate I, there is danger of clogging of spoil immediately behindrib ll, particularly in certain types of soil.

The various features of the invention may be diiferently embodied withinthe scope of the accompanying claims.

I claim:

1. In a bit of the class described, a blade support having a forwardlyslanting surface for supporting a cutting blade generally radially ofthe bit, a blade holder integrally secured at its upper edge to saidblade support and extending forwardly and downwardly parallel to saidsurface and spaced therefrom to provide a slot for receiving the cuttingblade, and a double edged reversible cutting blade adapted to be inseted in said slot, said blade and said holder having a radially extendinginterlocking tongue and groove to secure the bladefor insertion andremoval endwise thereof with either edge free for cutting and with theother edge spaced from the rear closure of the slot.

2. In a bit of the class described, a blade support having a forwardlyslanting surface for supporting a cutting blade generally radially ofthe bit, a blade holder integrally secured at its upper edge to saidblade support and extending forwardly and downwardly parallel to saidsurface and spaced therefrom to provide a slot for receiving the cuttingblade, and a double edged reversible cutting blade adapted to beinserted in said slot, said blade and said support having a radiallyextending interlocking tongue and groove to secure the blade forinsertion and removal endwise thereof with either edge free for cuttingand with the other edge spaced from the rear closure of the slot. 7

3. In a bit of the class described, for earth boring, a cutting bladeand a holder for said blade to secure the same at a flxed angle with itsfree cutting edge generally radial of the bit and extending downwardlyand forwardl to engage the soil, said blade having its cutting edgebeveled only on one side and being adapted to be secured in Place witheither side up to provide a predetermined selected angle of inclinationfor the cutting edge for different soil conditions.

4. In a bit of the class described, for earth boring, a cutting bladedisposed in a slanting slot in said bit with its free cutting edgegenerally radial of the bit and extending downwardly and forwardly toengage the soil, said blade having its cutting edge formed at differentangles on opposite sides and being adapted to be inserted in said sloteither side up to provide a predetermined selected angle of inclinationfor the cut ting edge, and means for interlocking. said blade and bit. a

5. In a bit of the class described, for earth boring, a cutting bladedisposed-in a slanting slot in said bit with its free cutting edgegenerally radial of the bit and extending downwardly and forwardly toengage the soil, said blade having its cutting edge formed at differentangles on opposite sides and being adapted to be inserted in said slot.either side up to provide a predetermined selected angle of inclinationfor the cutting edge, and said blade and bit having interlockingshoulders operable in either position of the blade for securing the samein place.

6. In a bit of the class described, for earth boring, a double edge flatcutting blade having a longitudinal groove in each side between thelongitudinal cutting edges and substantially parallel thereto forinterlocking with the bit, at least one of said grooves being disposedoff-center with respect to the center line of said blade to Provide fordifferent cutting depths for the respective blade edges upon thereversal of th blade.

7. In a bit of the class described, for earth boring, a double edge flatcutting blade having a. longitudinal groove in each side substantiallyparallel to the cutting edges of the blade for interlocking with thebit, said grooves being disposed oiT-center with respect to the centerline of said blade to provide for different cutting depths for therespective blade edges upon reversal of the blade, and said groovesbeing disposed opposite one another to provide for the turning over ofsaid blade. I

8. In a bit of the class described, for earth boring, a double edge flatcutting blade having its longitudinal cutting edges beveled to providedifferent cutting angles for the blade when Ireversed by turning'the.b1ade over in its holder and having a longitudinal groove in eachside be-,

tween the edges of the block for interlocking with the bit, said groovesbeing disposed opposite to one another to provide for the selectivereversal .of the blade.

9. In a bit of the class described, for earth boring, a circularhorizontal plate having an open sector through which spoil rises over aslanting.

generally radially disposed cutting blade, a spiral conveyor flightdisposed with its lower end edge adjacent the blade for receivingspoiltherefrom,

a central vertical support for said flight, a trap door covering saidopen sector and adapted to pivot upwardly on the spoil, and a hingebracket on said plate for hinging said trap door thereto, said bracketproviding the pivot line of said door at a level substantially above thetop of said plate and in a direction substantially parallel to a radiusnear the center of said open sector thereby facilitating pivoting of thedoor free from interference by said central support.

10. In a bit of the class described, for earth sector-like opening, theforwardly facing edge bounding said opening being of substantialthickness and having its face slanting upwardly toward the rear tosupport a cutting blade at an angle thereon, a blade holder extendingparallel to the face of said edge and spaced above the same forreceiving a cutting blade therebetween,

' a cutting blade disposed in said space and extending substantiallyradial of said support with its forward and downward edge disposed forcutting, and fixed interlocking shoulders between the blade and saidholder to secure the blade against thrust forces and requiring the bladeto be inserted and removed. by endwise movement radially of the support,the top surface of the holder being substantially free from obstructionto the movement of dirt thereover.

12. In a rotary bit of the class described for earth boring, a disc-likeblade support having a sector-like opening, the forwardly facing edgebounding said opening being of substantial thickness and having its faceslanting upwardly toward the rear to support a cutting blade at an anglethereon, a blade holder extending parallel to the face of said edge'andspaced abov the samefor receiving a cutting blade therebetween, acutting blade disposed in said space and extending substantially radialof said support with its forward and downward edge disposed for cutting,and fixed interlocking shoulders between the blade and said holder tosecure the blade against thrust forces and requiring the blade to beinserted and removed by endwise movement radially of the support, thetop surface of the holder being substantially free from obstruction tothe movement of dirt thereover, and a removable pin adapted to interlockthe blade with said holder to prevent accidental displacement of theblade radially of the support.

13. In a rotary bit of the class described for earth boring, a disc-likeblad support having a sector-like opening, the forwardly facing edgebounding said opening being of substantial thickness and having its faceslanting upwardly toward the rear to support a cutting blade at an anglethereon, a blade holder extending parallel to the face of said edge andspaced above the same for receiving a cutting blade therebetween, acutting blade disposed in saidspace and extending substantially radialof said support with its forward and downward edgedisposed for cut- Iting, and fixed interlocking shoulders between the blade and saidsupport to secure the blade against thrust forces and requiring'theblade to be inserted and removed by endwise movement radially of thesupport, the top surface of the holder being substantially free fromobstruction to the movement of dirt thereover.

14. In a bit of the class described for earth boring, a fiat cuttingblade having its upper and lower edges shaped for cutting and adapted tobe held with one of its cutting edges extending horizontally in agenerally forward and downward direction, said blade having alongitudinal groove in at least one side intermediate and parallel tosaid cutting edges for interlocking the same with the bit to transmitthrust forces therebetween.

CHARLES W. KANDLE.

